The trick is to use the caller function. Example:

a.pl: unless (caller[0] =~ /main/) { print "a was called directly\n"; }
b.pl:do "a.pl";

Now, if a.pl is called directly, it will print the message, but if b.pl is called first, and a.pl is called from b.pl, it will not print the message.

As a concrete example of this:

My::Standalone.pm

unless (caller() =~ /main/) {
    My::Standalone->run();
} else {
    @My::Standalone::EXPORT = qw[run];
}
package My::Standalone;
use strict;
use warnings;
use Exporter;

our @ISA = qw(Exporter);

sub run {
    my($self) = shift || caller();
    print "See, I do something\n";
}

1;
[download]

You can then call this with any of the following:

• perl My/Standalone.pm
• perl -MMy::Standalone -e"run();"

or include it in a script:

test.pl

#!perl
use strict;
use warnings;
use My::Standalone;

print "Do something\n";
run(); # Call the run function
exit;
[download]

use FindBin ();  # get actual path of this script
print "Path of script is: $FindBin::Bin\n"; # no namespace pollution
[download]

Otherwise, you could set a global Variable in the main-package (e.g. assign $0 to it) and ask it in every packages BEGIN-Block if it is already defined... Best regards,
perl -le "s==*F=e=>y~\*martinF~stronat~=>s~[^\w]~~g=>chop,print"

I think __PACKAGE__ is what you want.

$ perl -e'print __PACKAGE__,$/'
main
$
[download]

After Compline,
Zaxo

__PACKAGE__ always prints out the current package, and in a script (that doesn't declare its own package) that has been included via "do" or "require", __PACKAGE__ still is "main". An inelegant solution is a create a global variable when the first script begins it's main path of execution, and check for that in each submodule. But the elegant way escapes me.

  __FILE__ eq $0 and main();
[download]

  BEGIN { require "myfile" }
[download]

  use myfile;
[download]

Cheers,
Hrakaroo